Disposal of coal tar pitch



Patented Dec. 6, 1932 UNITED "STATES PATENT. oluuclaz OHZN' MORRIS WEISS, OF NEW YORK, N. Y.', ASSIGNOR, BY MESNE ASSIGlillYIIFl-llTS, TO THE BARRETT COMPANY, OF NEW YORK, N. Y., A CORPORATION OF JERSEY DISPOSAL OF GOA L TAR PITCH No Drawing.

This invention relates to the disposal of coal tar obtained at by-product coke oven plants. of distillate oil from the coal tar and at the same time dispose of the residualpitch in an economical and useful manner. Another object is to improve the quality of coke obtained in the by-product coke oven. Further objects will appear upon reading the specification.

In the manufacture of coke in by-product coke ovens, bituminous coal is destructively distilled and there are obtained gas, aqueous ammonia liquor, tar and coke. At present at a majority of Icy-product coke oven plants,

the tar is burned as fuel although on the average by distillation a yield of from 50 to 65% of salable creosote oil could be obtained from the tar which creosote oil would have a 29 ready market in View of the fact that the United States production of creosote oil is not enough to half satisfy the demand, the balance being imported from abroad. The reason for this condition is that there is at present no commercial outlet for pitch which would absorb the amounts which would be thrown on the market if the by-product coke oven tar which is now burned were distilled.

T he present tonnage outlets for pitch are in 30 road .compounds, roofing and briquette pitches, none'of which grades affords the maximum yields of creosote oil obtained when the tars are distilled to a residual air melting point of 225 to 300 F. or higher, even up to 500 F. air melting point. For example, on the average when road compounds are made there isobtained only 5 to 15% distillate all of which is too light-boiling to meet standard creosote oil specifica tions. With roofing or briquette pitches 25 to 40% of distillate may be obtained of which 70' to 90% is usable as creosote oil, depending on the extent to which the distillation is carried. With pitches of 225 F. or higher,

from 60 to 75% of distillate maybe obtained,

substantially all of which will meet the standard creosote oil specifications; Thepitch obtained in this way, however, is very hard and brittle and has no tonnage markets at the One object is to obtain a maximum per ton of coal which tar is distilled for creo- Application filed September 26, 1927. Serial No. 222,207.

present time. My process takes advantage of this nature as will be shown later.

I have found that coal tar pitch of 225" F. melting point or higher may, be easily comminuted orpulverized and mixed with the coal to be coked in the coke oven and in this way acquires a value at least equal to thecoal charged to the ovens. The coke is improved in strength and its ash and sulphur content reduced in proportion to theproportion of pitch charged. The pitch may be mixed with the coal before charging or during the charging of the ovens. 1 If all the tar is handled according to my process, the pitch charged will amount to from 1 to 3.5% of the coal used and its addition up to these amounts does not require any changes in the ordinary coke oven practice.- 7

In order to specifically point out the invention, the following example is given but it is not my intention to limit the scope of my invention by this example which is for illustrative purposes only.

Bituminous coal is coked in an ordinary by-product coke oven which is a narrow vertical chamber the walls of which are heated by external flues. A coke of 10% ash ordinarily results from this coking operation. As a byproduct 120 lbs. of tar are obtained sote oil and a residue of 60 lbs. pitch per ton of coal secured. This pitch is mixed in with the coal to be coked so that in later charges we have 60 lbs. pitch per ton of coal. These charges may be coked in a similar manner, i. e. in thin vertical layers, the coking temperature being maintained by applying heat to the sides of thesethin layers. The ash inthe resulting coke will then be approxim ately 9.8%. It is not necessary to mix the residual pitch with the same amount of coal from which it is derived. In the above example the pitch amounts to 3% of the coal.

One future lot of coal might have 6% pitch mixed in and another lot none; the proportioning of various batches may be in any I desired ratio depending on the desires of the coke oven operator but from a standpoint of proper coke oven operation it is not ad- 1.29

visable to use more than 15 parts ofpitch l may amount to as much as 25 to 50 per ton of coal coked, depending on the value of fuel oil and creosote oil respectively. This is ac complished by distilling the tar from a byproduct coke oven so as to obtain a pitch hard enough to be ground or otherwise comminuted and using said pitch in admixture signature.

coking said residuum in admixture with bituminous coking coal.

8WThe method of treating coal tar which comprises distilling the tar until a residuum of at least 225 F. air melting point is obtained, comminutin said residuum, admixing the comminute material with bituminous coking coal, and coking the mixture, In testimony whereof, I hereby aflix'my JOHN Momus WEISS.

with coal in a by-product coke oven. Knowing that the pitch can be disposed of, no matter how high its melting point, it is possible to run for a maximum yield of creosote oil at all times without considering the character of the residual pitch.

Having thus described my invention, I claim:

1. The processing of by-product coke oven tar comprising distilling the tar until a residual pitch hard enough to be ground at ordinary atmospheric temperatures is obtained and coking said pitch in admixture with bitliminous coking coal in the proportion of not over 15 parts of pitch to 100 parts of coal and producing coke therefrom.

2. The processing of coal tar comprising distilling the tar until a residuum of at least 225 F. air melting point is obtained and coking said residuum in. admixture with bituminous coking coal. p

3. The processing of coal tar comprising distilling the tar until a residuum of at least 225 F. air melting point is obtained and coking said residuum in admixture with coal in the proportions of not over 15 parts of residuum to 100 parts of bituminous cokin 0 coal.

4. The processing of coaltar comprising distilling the tar until a residual pitch hard enough to be ground at atmospheric temper.- ature is obtained, coking said pitchin admixture with bituminous coking coal by forming thin vertical layers ofthe mixture of coal and the pitch, applying heat to the sides of these thin layers, and converting the mixture to coke.

5. The processing of coal tar comprising distilling the tar until a residuum of at least 225 F. air melting point is obtainedand coking said residuum in admixture with bituminous coking coal in amounts containing not more than 3.5% of pitch.

6. The processing of coal tar comprising distilling the tar until a residuum of at least 225 F. air" melting point is obtained and coking" said residuum in admixture with bituminous coking coal in amounts containlng not. more than 6.0% of pitch.

7. The processing of coal tar comprising distilling the tar until a residuum of at least 300 F. air melting point is obtained and- 

